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The Middle Proterozoic Jacobsville Sandstone, located on the upper peninsula, Michigan, is the youngest rift- related sedimentary unit in the 1.1 Ga Midcontinent rift. Although outcrops of the Jacobsville Sandstone along the Lake Superior shoreline and in river gorges are well studied, these outcrops represent stratigraphically only the upper 300-400 feet of the estimated 9,000 feet thick Jacobsville Sandstone. I used drill cores and newly-studied outcrop samples; 1) to characterize stratigraphically continuous sections; 2) to compare the Jacobsville Sandstone in subsurface with the Jacobsville Sandstone in outcrop; 3) to identify lateral and vertical variations in texture and petrographic composition within the Jacobsville Sandstone; and 4) to determine petrographic provenance of the Jacobsville Sandstone.